The present invention relates to an extracorporeal blood treatment machine and to an integrated treatment module that can be used on said machine.
The object of the invention can be used for instance in intensive therapy machines which can carry out a plurality of different blood treatments.
Extracorporeal treatments generally consists in taking blood from the patient, in treating said blood when it is outside the patient's body and then in re-circulating the blood thus treated.
The treatment typically consists in removing from the blood unwanted and/or dangerous substances, as well as excess liquid in patients who cannot autonomously carry out said operations, such as for instances patients suffering from temporary or permanent kidney problems.
For instance, it may be necessary to add or remove substances from blood, to keep a correct acid/base ratio or also to remove fluid excess from the body.
The extracorporeal treatment is generally obtained by removing blood from the patient, by letting the blood flow within a filtration unit where a semipermeable membrane ensures the exchange of suitable substances, molecules and fluids.
Generally though not necessarily, said exchange is carried out by letting a given biological fluid ensuring the aforesaid exchanges pass in counter-current and within a secondary chamber of the filtration unit.
It should be noted that currently used machines can enable different types of blood treatment.
In the ultrafiltration treatment the substances and fluids to be eliminated are removed by convection from the blood, pass through the semipermeable membrane and are led towards the aforesaid secondary chamber.
In hemofiltration treatments part of the molecules, substances and fluids present in the blood pass through the membrane by convection as in the ultrafiltration treatment, although further necessary elements are added to the blood; typically a suitable fluid is infused directly into the blood before or after the latter passes through the filtration unit and anyhow before it is carried back into the patient.
In haemodialysis treatments a fluid containing material to be transferred into the blood is introduced into the secondary chamber of the filtration unit. The unwanted material flows through the semipermeable membrane from the blood into the secondary fluid and the desired substances/molecules from the secondary fluid can pass through the membrane as far as the blood.
In hemodiafiltration treatments the blood and the secondary fluid exchange their respective substances/molecules as in haemodialysis and, in addition, a fluid is infused into the blood as in haemofiltration treatments.
Obviously, in order to carry out each of said extracorporeal blood treatments, the blood has to be removed from a patient's vein or artery, suitably circulated in the machine and then re-introduced into the patient.
As is also known, blood treatment machines for intensive therapy have to be ready as fast as possible for an immediate use for any possible emergency.
Obviously, to this purpose the machine must not require either preliminary sanitizing operations or long pre-assembling operations of the various components for the various therapies.
As is known, intensive therapy machines are present on the market and are currently used, in which a blood circuit comprises a line for taking blood from the patient, which carries said blood to a filtration cartridge, and an outlet line from the filtration cartridge, which carries the treated blood back into the patient's body.
The machine is then equipped with a circuit for the passage of dialysis fluid; also said circuit has an intake line leading into the filtration unit, which is supplied by a sterile bag containing the dialysis liquid, and has also an outlet line enabling the passage of a fluid which has received by convection/diffusion the dangerous substances and molecules from the blood towards a collection bag for their subsequent removal.
Said machine is further equipped with an infusion line allowing—with suitable doses—to transfer directly into the blood upstream from the filtration unit the content of another liquid bag, thus adding the necessary products into the blood.
A known intensive therapy machine is further equipped with a suitable syringe containing for instance heparin as blood anticoagulant, the latter being added to the blood taken from the patient so as to avoid the creation of dangerous clots within the circuit.
The structure and circuitry mentioned above are generally defined by a single integrated module attached to the machine body.
It is evident that in order to enable the immediate use of the machine, the fluid bags referred to above have to be present and already sterile, so as to be directly and easily connected to their respective tubes, the latter also being sterile and disposable.
The machine is further equipped with a suitable control unit managing the flow of fluids by means of suitable peristaltic pumps and respective sensors associated to the circuit.
It is evident that by suitably setting the control unit said machine can selectively carry out one or more of the extracorporeal blood treatments described above (i.e. ultrafiltration, haemofiltration, haemodialysis and haemodiafiltration).
The machine described above, though being today quite a vanguard device for extracorporeal blood treatments in intensive therapies, has proved to be susceptible of several improvements.
In particular, a first intrinsic drawback in intensive therapy machines is related to the limited availability of fluids for operations involving the exchange of substances by convection/diffusion within the filter and for pre- or post-infusions into the blood line.
Said limitation is obviously related to the necessary use of pre-packaged sterile fluid bags typically containing 6 kg of dialysis liquid.
It is evident that the pre-established fluid amount to be used imposes some limitations, in particular in the case of therapies with large exchange of fluids, which would sometimes be extremely suitable in emergency cases.
On the other hand, it is not possible to use larger fluid amounts in intensive therapies since suitably treated water taken from the water network cannot be used as exchange fluid in short times; indeed, this would involve long operations for installing the devices for in-line preparation of sterile liquids; moreover, it is not possible to use bags with higher amounts of liquids due to the obvious problems involving transport and management of said containers by the personnel.
Another problem of known intensive therapy machines consists in achieving an optimal management of the administration of anticoagulant substances which are necessary for a good working of the machine.
In particular, today known intensive therapy machines cannot manage effectively the use of regional anticoagulation methods, such as for instance citrate-based methods, since the use of said techniques requires the administration of further solutions recovering the blood ion balance before carrying the treated blood back into the patient's body.